NOS 30's can be purchased from several companies. Check below:
http://www.antiqueradios.com/resources/
I am sending you some information by email. Once you see it you may not want to use 30's.
Norm
: Sir('s):I have a 1924 Radiola III....I use (NOS) 30's...a Pair to Run My Radio. Does anyone have a Pair of (NOS) 30's For Sale? Or! What have you? Thanks. Rick USMC,Ret.